In various chemical, biochemical or pharmaceutical applications local transfer of fluids is involved. A common way for such transfer is by means of a pipette wherein the fluid can be retrieved into the pipette via a needle, the pipette can be relocated and then the fluid can be dispensed at a final location out of the pipette. Often, the fluids to transfer need to be kept in a certain temperature range which can be achieved by heating the needle of the pipette.
For example, many processes for creating certain chemical compounds involve solutions comprising a solute dissolved in a solvent. In order to be able to dissolve a favourable amount of solute, the solution is often equilibrated at an elevated temperature close to the boiling point of the solvent. In order to prevent crystal formation or precipitation caused by cooling, such solutions can be transferred using a heatable pipette.
As an example of an according heatable pipette, WO 03/014732 A1 discloses a pipette system comprising a needle for dispensing or retrieving a liquid and a heat sink for maintaining a specific temperature of the liquid. The heat sink encloses a section of the needle in order to be capable of transmitting heat to the needle. Since only a section of the needle is heated by means of the heat sink, the temperature of the liquid inside the needle decreases with increasing distance to the heat sink. Particularly, if needles are used having a large section not being enclosed by the heat sink, said decrease of temperature can cause crystal formation or precipitation to a certain extent.
In U.S. Pat. No. 6,260,407 B1 a pipette is shown comprising a double walled needle. Between the two walls a temperature control element is arranged being capable of heating more or less the entire length of the needle. Said element can for example be arranged as a resistive wire being wound between the two walls of the needle or as an according fluid containing tubular coil. Such arrangements are usually not efficiently feasible in small dimension.
Therefore there is a need for a heatable pipette with a needle, being capable of heating more or less the entire length of the needle and being simply producible in comparably small dimensions.